Fuel pump clearance for Monitor heaters should be either 12 inches or 24 inches overhead, 24 inches in the front and 18 inches on the sides, according to the manufacturer’s instructions. The exact heater clearances, however, depend on the product model.
Clearances for the M20, M21, M22, MP40, and MP41 models should be 6 inches on the back and right side, 10 inches on the left side, 24 inches above the heater and 39 inches in the front. Recommended clearances for the GF3800, M422 and M441 models are 6 inches on the right side, 10 inches on the left side, 24 inches above the heater, 39 inches in the front and 5 1/2 inches on the back. Except for the right side clearance, which should be 6 inches, clearances for the GF500 and GF200 models are the same. GF1800, M2400 and M2200 should be installed with the clearances of 6 inches on the sides, 5 1/2 inches on the back, 39 inches in the front and 12 inches on the top.